Qhov yooj yim bandpass lim yog LC lim - lawv siv inductors thiab capacitors (txawm hais tias ib txwm muaj qee cov resistors ntxiv hauv Circuit Court uas cuam tshuam rau kev ua haujlwm).
Cov Cheebtsam no tuaj yeem txuas rau hauv series lossis parallel, thiab cov txiaj ntsig tau raug hu uaseries resonantcircuits thiab parallel resonant circuits, feem. Lo lus resonance yog siv vim hais tias cov circuits teb rau tej zaus, ib yam li cov hlua ntawm lub violin lossis guitar. Yog li ntawd, lawv feem ntau hu ua tuning circuits.
Qhov no qhia qee qhov piv txwv ntawm cov circuits txuas nrog ntau txoj hauv kev. Lub resonant zaus ntawm ob qho tib si series thiab parallel circuits yog vim cov nyhuv tsis kam, qhov twg XL ntawm inductor yog sib npaug rau Xc ntawm lub capacitor. Peb tuaj yeem tau txais qhov resonance zaus los ntawm kev daws qhov sib npaug no
Qhov twg f yog zaus, L yog inductance, C yog capacitance, sawv cev zaus:
Nyob rau hauv ib tug parallel tuned Circuit Court, capacitors thiab inductors txuas nyob rau hauv parallel, yog li ntawd lawv muaj tib voltage. Ntawm qhov resonance zaus, peb kuj muaj tias lawv cov reactants sib npaug. Raws li Ohm txoj cai ntawm AC circuits, yog tias inductors thiab capacitors muaj tib qhov voltage thiab reactance, lawv kuj yuav tsum muaj tib yam tam sim no. Yog li ntawd lawv txhua tus muaj tib yam tam sim no. Tab sis vim hais tias ib qho ntawm cov tam sim no ua rau qhov hluav taws xob nce mus txog 90 "thiab lwm yam tam sim no ua rau qhov hluav taws xob poob ntawm 90", lawv yog 180 "sib nrug. Yog li ntawd, cov kev taw qhia ntawm cov tam sim no yog qhov sib txawv, ib qho nce thiab lwm qhov poob. Yog li ntawd, tam sim no nyob rau hauv cov xaim ua rau lub thib ob tuning Circuit Court yuav tsum yog xoom.
Qhov xwm txheej sib txawv tshwm sim hauv aseries resonant (tseem hu ua series resonant ntaus ntawv)Circuit Court. Ntawm no, cov capacitors thiab inductors txuas nrog hauv koob, yog li tam sim no yog tib yam. Lub sijhawm no, qhov hluav taws xob ntawm ib lub electrode coj qhov tam sim no, thaum qhov hluav taws xob ntawm lwm lub electrode lags tom qab tam sim no los ntawm 90 ". Yog li ntawd, ob qhov voltages yog 180 nti sib nrug. Ntawm resonance (lwm txoj kev hais tias 'ntawm resonance zaus'), lawv cov reactants sib npaug, yog li lawv cov voltages sib npaug, tab sis opposite. Yog li ntawd, tag nrho cov voltage ntawm tag nrho cov circuits yog tam sim no. zoo li a luv luv Circuit Court (tseem muaj tam sim no, tab sis tsis muaj hluav taws xob dhau los).
Yog li ntawd, peb tau tsim cov cai hauv qab no:
Thaum lub sij hawm resonance, lub parallel tuned Circuit Court nthuav tawm ib qho qhib Circuit Court.
Thaum lub sij hawm resonance, lubseries resonantCircuit Court qhia ib tug luv luv Circuit Court.
Ntawm lwm zaus, ob lub circuits muaj ib qho impedance. Mus txog qhov resonant zaus, lub Circuit Court tsis qhib kiag li (rau kev sib txuas sib txuas) lossis luv luv (rau kev hloov kho), tab sis tseem nyob ze heev. Qhov deb ntawm qhov resonant zaus, qhov me me ntawm Circuit Court, thiab tej zaum yuav qhib los yog luv circuits.
Ob leeg ntawm cov circuits no tuaj yeem ua cov lim dej xaiv, tso cai rau qee zaus kom dhau mus thiab tiv thaiv lwm tus los ntawm kev hla. Lawv tuaj yeem txuas cov kab hluav taws xob sib txuas ntawm ob qho kev qhia yooj yim, xws li (a) thiab (b) (nyob rau hauv rooj plaub twg lub teeb liab yuav luv dua nyob ntawm qhov impedance ntawm lub Circuit Court), lossis lub teeb liab yuav tsum dhau los ntawm LC Circuit Court los ntawm kev tawm tswv yim rau cov zis raws li qhia hauv (c) thiab (d) (qhov twg nws yuav ntau dua lossis tsawg dhau los ntawm nyob ntawm qhov impedance ntawm Circuit Court).
Siv Circuit (a) ua piv txwv. Thaum lub sij hawm resonance, lub parallel tuned Circuit Court nthuav tawm ib qho qhib Circuit Court, nrog rau feem ntau ntawm cov teeb liab input ncaj qha mus txog cov zis los ntawm resistors. Raws li qhov sib txawv cov zis loads, tej zaum yuav muaj tam sim no nyob rau hauv lub series resistor, yog li tej zaum yuav muaj voltage poob, tab sis peb yuav tsis quav ntsej nws. Txawm li cas los xij, sib nrug los ntawm resonance, qhov kev hloov kho tsis tau qhib lawm; Nws ua rau qhov nce tam sim no dhau los ntawm cov resistor series, uas ua rau muaj qhov nce ntawm qhov poob qis. Qhov deb ntawm resonance, qhov ntau dua qhov txo qis thiab qhov me dua qhov tso zis voltage.
Yog tias peb khaws cov input voltage tsis tu ncua tab sis hloov qhov zaus, thiab tom qab ntawd teeb tsa kev sib raug zoo ntawm cov zis voltage thiab zaus, peb tau txais daim duab zoo ib yam li daim duab (a). Peb pom tias lub ncov ntawm qhov tso zis tshwm sim ntawm qhov resonance zaus thiab muaj qhov txo qis ntawm ob sab. Muaj tseeb ib qho kev sib tw zaus dhau los ze ntawm lub resonance, thaum lub zaus deb ntawm resonance raug txo qis (txawm tias tsis nres kiag li). Vim tias muaj ib lub suab nrov uas tuaj yeem dhau mus, nws hu ua bandpass lim. Lub Circuit Court (c) nyob rau hauv daim duab kuj yog ib tug bandpass lim; Vim lub fact tias cov series resonant circuits luv luv Circuit Court ntawm xob laim taw tes, qhov zaus ntawm resonance dhau los ntawm (thiab nyob ze), thaum lub zaus txo qis dua vim hais tias lub series resonant Circuit Court tam sim no muaj ib co reactance.
Circuits (b) thiab (d) ua qhov tsis sib xws - lawv nres lub teeb liab ntawm resonance; Circuit (b) yog ua tiav los ntawm shortening lub teeb liab, thaum Circuit Court (d) yog tiav los ntawm kev qhib txoj kev ntawm lub input thiab tso zis. Txawm tias ze rau resonance, lawv yuav ua rau lub teeb liab tsis muaj zog, yog li lawv yuav nres (lossis tsis muaj zog) ib lub suab nrov raws li pom hauv daim duab (b). Yog li ntawd, lawv hu ua band nres lossis band nres lim.
Thov nco ntsoov qhov zoo sib xws ntawm qhov no thiab RC low -pass lossis high pass lim tau tham hauv tshooj dhau los. Txawm hais tias peb tab tom hais txog qhov txiav tawm zaus ntawm no, qhov tseeb nkhaus qhia tau hais tias 'kev txiav tawm' yog qhov poob qis heev. Kuj tseem muaj kev hloov maj mam hloov ntawm ob sab ntawm qhov resonance zaus.